PPRuNe Forums - A320: 500fpm in DES mode

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- - A320: 500fpm in DES mode (https://www.pprune.org/tech-log/496591-a320-500fpm-des-mode.html)

J.L.Seagull

27th September 2012 11:57

A320: 500fpm in DES mode

It is plainly stated in the FCTM that the A320 will do 1000fpm rate if descent, if in managed DES mode, and below profile, until it catches up with the profile.

However, I've observed that below 10000ft, while still in DES mode, the aircraft now does 500fpm! I can't seem to find any reference in any manuals to explain this behaviour.

Any ideas?

Maz11

27th September 2012 12:08

FCOM : PRO-NOR-SRP-01-60

Quote:

If the aircraft is flying at an altitude that is lower than either the descent speed limit altitude, or the destination elevation +5 000 ft:

The FMGS maintains the V/S at - 500 ft/min and the target speed, until the aircraft reaches the altitude constraint or intercepts the descent profile.

Hope this helps

J.L.Seagull

27th September 2012 12:12

Brilliant! Thanks... this is exactly what I was looking for.

Guess I was just too tired, and browsed thru this page without the info actually sinking in! :)

Easy226

27th September 2012 12:12

Maybe this is what your after...

DSC-22-30-70-50 P10/12 - Aircraft below the descent profile.....

If the aircraft is flying at an altitude that is lower than either the descent speed limit altitude or the destination elevation +5000 ft:

The FMGS maintains the VS at 500 ft/min and the target speed, until the aircraft reaches the altitude constraint or intercepts the descent profile.

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